Step 4: Configure the router to advertise the 192.168.10.4/30 network attached to theSerial0/0/1 interface.R1(config-router)#network 192.168.10.4 0.0.0.3 area 0R1(config-router)#Step 5: When you are finished with the OSPF configuration for R1, return to privilegedEXEC mode.

R1(config-router)#end%SYS-5-CONFIG_I: Configured from console by consoleR1#Task 5: Configure OSPF on the R2 and R3 RoutersStep 1: Enable OSPF routing on the R2 router using the router ospf command.Use a process ID of 1.R2(config)#router ospf 1R2(config-router)#

Step 2: Configure the router to advertise the LAN network 10.10.10.0/24 in the OSPFupdates.

R2(config-router)#network 192.168.10.8 0.0.0.3 area 0R2(config-router)#end%SYS-5-CONFIG_I: Configured from console by consoleR2#

Step 5: Configure OSPF on the R3 router using the router ospf and networkcommands.Use a process ID of 1. Configure the router to advertise the three directly connected networks.When you are finished, return to privileged EXEC mode.R3(config)#router ospf 1R3(config-router)#network 172.16.1.32 0.0.0.7 area 0R3(config-router)#network 192.168.10.4 0.0.0.3 area 0R3(config-router)#00:17:46: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.10.5 on Serial0/0/0from LOADING to FULL, Loading DoneR3(config-router)#network 192.168.10.8 0.0.0.3 area 0R3(config-router)#00:18:01: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.10.9 on Serial0/0/1from EXCHANGE to FULL, Exchange DoneR3(config-router)#end%SYS-5-CONFIG_I: Configured from console by consoleR3#Notice that when the networks for the serial links from R3 to R1 and R3 to R2 are added to theOSPF configuration, the router sends a notification message to the console stating that aneighbor relationship with another OSPF router has been established.Task 6: Configure OSPF Router IDsThe OSPF router ID is used to uniquely identify the router in the OSPF routing domain. A routerID is an IP address. Cisco routers derive the Router ID in one of three ways and with the followingprecedence:1. IP address configured with the OSPF router-id command.2.Highest IP address of any of the router’s loopback addresses.3.Highest active IP address on any of the router’s physical interfaces.Step 1: Examine the current router IDs in the topology.Since no router IDs or loopback interfaces have been configured on the three routers, the routerID for each router is determined by the highest IP address of any active interface.What is the router ID for R1? ____________________What is the router ID for R2? ____________________What is the router ID for R3? ____________________CCNA ExplorationRouting Protocols and Concepts:OSPF Lab 11.6.1: Basic OSPF Configuration Lab

When a new Router ID is configured, it will not be used until the OSPF process is restarted.Makesure that the current configuration is saved to NRAM, and then use the reload command torestart each of the routers..

When the router is reloaded, what is the router ID for R1? ____________________When the router is reloaded, what is the router ID for R2? ____________________When the router is reloaded, what is the router ID for R3? ____________________Step 4: Use the show ip ospf neighbors command to verify that the router IDs havechanged.R1#show ip ospf neighbor

Step 5: Use the router-id command to change the router ID on the R1 router.Note:Some IOS versions do not support the router-id command. If this command is notavailable, continue to Task 7.R1(config)#router ospf 1R1(config-router)#router-id 10.4.4.4Reload or use “clear ip ospf process” command, for this to take effectIf this command is used on an OSPF router process which is already active (has neighbors), thenew router-ID is used at the next reload or at a manual OSPF process restart. To manually restartthe OSPF process, use the clear ip ospf process command.

R1(config)#router ospf 1R1(config-router)#no router-id 10.4.4.4Reload or use “clear ip ospf process” command, for this to take effectStep 8: Restart the OSPF process using the clear ip ospf process command.Restarting the OSPF process forces the router to use the IP address configured on the Loopback0 interface as the Router ID.

R1(config-router)#endR1#clear ip ospf processReset ALL OSPF processes? [no]:yesR1#Task 7: Verify OSPF OperationStep 1: On the R1 router, Use the show ip ospf neighbor command to view theinformation about the OSPF neighbor routers R2 and R3. You should be able to see theneighbor ID and IP address of each adjacent router, and the interface that R1 uses to reach thatOSPF neighbor.R1#show ip ospf neighborNeighbor ID Pri State Dead Time AddressInterface10.2.2.2 0 FULL/- 00:00:32 192.168.10.2Serial0/0/010.3.3.3 0 FULL/- 00:00:32 192.168.10.6Serial0/0/1R1#

Step 2: On the R1 router, use the show ip protocols command to view informationabout the routing protocol operation.Notice that the information that was configured in the previous Tasks, such as protocol, processID, neighbor ID, and networks, is shown in the output. The IP addresses of the adjacentneighbors are also shown.CCNA ExplorationRouting Protocols and Concepts:OSPF Lab 11.6.1: Basic OSPF Configuration Lab

<output omitted>On most serial links, the bandwidth metric will default to 1544 Kbits.If this is not the actualbandwidth of the serial link, the bandwidth will need to be changed so that the OSPF cost can becalculated correctly.Step 3:Use the bandwidth command to change the bandwidth of the serial interfaces ofthe R1 and R2 routers to the actual bandwidth, 64 kbps.R1 router:R1(config)#interface serial0/0/0R1(config-if)#bandwidth 64R1(config-if)#interface serial0/0/1R1(config-if)#bandwidth 64

<output omitted>Step 5: Use the ip ospf cost command to configure the OSPF cost on the R3 router.An alternative method to using the bandwidth command is to use the ip ospf costcommand, which allows you to directly configure the cost. Use the ip ospf cost command tochange the bandwidth of the serial interfaces of the R3 router to 1562.R3(config)#interface serial0/0/0R3(config-if)#ip ospf cost 1562R3(config-if)#interface serial0/0/1R3(config-if)#ip ospf cost 1562

Step 6: Use the show ip ospf interface command on the R3 router to verify that thecost of the link the cost of each of the Serial links is now 1562.R3#show ip ospf interface<output omitted>

<output omitted>Task 10: Redistribute an OSPF Default RouteStep 1: Configure a loopback address on the R1 router to simulate a link to an ISP.R1(config)#interface loopback1

%LINK-5-CHANGED: Interface Loopback1, changed state to up%LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback1, changedstate to up

R1(config-if)#ip address 172.30.1.1 255.255.255.252Step 2: Configure a static default route on the R1 router.Use the loopback address that ha been configured to simulate a link to an ISP as the exitinterface.R1(config)#ip route 0.0.0.0 0.0.0.0 loopback1R1(config)#Step 3: Use the default-information originate command to include the static routein the OSPF updates that are sent from the R1 router.R1(config)#router ospf 1R1(config-router)#default-information originateR1(config-router)#

R3(config-router)#auto-cost reference-bandwidth 10000% OSPF: Reference bandwidth is changed.Please ensure reference bandwidth is consistent across allrouters.Step 2:Examine the routing table on the R1 router to verify the change in the OSPF costmetric.Notice that the values are much larger cost values for OSPF routes.R1#show ip route

After 20 seconds the Dead Timer on R1 expires. R1 and R2 loose adjacency because the DeadTimer and Hello Timers must be configured identically on each side of the serial link between R1and R2.Step 5: Modify the Dead Timer and Hello Timer intervals.Modify the Dead Timer and Hello Timer intervals on the Serial 0/0/0 interface in the R2 router tomatch the intervals configured on the Serial 0/0/0 interface of the R1 router.CCNA ExplorationRouting Protocols and Concepts:OSPF Lab 11.6.1: Basic OSPF Configuration Lab

Step 6: Use the show ip ospf neighbor command on R1 to verify that the neighboradjacency with R2 has been restored.Notice that the Dead Time for Serial 0/0/0 is now much lower since it is counting down from 20seconds instead of the default 40 seconds. Serial 0/0/1 is still operating with default timers.R1#show ip ospf neighborNeighbor ID Pri State Dead Time AddressInterface10.2.2.2 0 FULL/- 00:00:19 192.168.10.2Serial0/0/010.3.3.3 0 FULL/- 00:00:34 192.168.10.6Serial0/0/1R1#Task 12: Document the Router Configurations.On each router, capture the following command output to a text file and save for future reference:Running configurationRouting tableInterface summarizationOutput from show ip protocolsCCNA ExplorationRouting Protocols and Concepts:OSPF Lab 11.6.1: Basic OSPF Configuration Lab

Task 6: Configure OSPF on the DRother RouterConfigure the OSPF process on the router with the lowest router ID last. This router will bedesignated as DRother instead of DR or BDR.Step 1: Use the router ospf command in global configuration mode to enable OSPF onthe R1 router.Enter a process ID of 1 for the process-ID parameter. Configure the router to advertise the192.168.1.0/24 network. Use an area ID of 0 for the OSPF area-id parameter in the networkstatement.

Step 3: Use the ip ospf priority interface command to change the OSPF priority ofthe R2 router to 0. A priority of 0 causes the router to be ineligible to participate in an OSPFelection and become a DR or BDR.

R2(config)#interface fastEthernet0/0R2(config-if)#ip ospf priority 0R2(config-if)#endStep 4: Shut down and re-enable the FastEthernet0/0 interfaces to force an OSPF election.The FastEthernet0/0 interfaces of each of the routers can be shut down and re-enabled to forcean OSPF election. Shut down the FastEthernet0/0 interface on each of the three routers. Noticethat as the interfaces are shut down the OSPF adjacencies are lost.CCNA ExplorationRouting Protocols and Concepts:OSPF Lab 11.6.1: Basic OSPF Configuration Lab

%LINK-5-CHANGED: Interface FastEthernet0/0, changed state toadministratively down%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0,changed state to down02:17:22: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.31.22 onFastEthernet0/0 from FULL to Down: Interface down or detached02:17:22: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.31.33 onFastEthernet0/0 from FULL to Down: Interface down or detachedR2:R2(config)#interface fastethernet0/0R2(config-if)#shutdown

%LINK-5-CHANGED: Interface FastEthernet0/0, changed state toadministratively down%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0,changed state to down02:17:06: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.31.33 onFastEthernet0/0 from FULL to Down: Interface down or detached02:17:06: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.31.11 onFastEthernet0/0 from FULL to Down: Interface down or detachedR3:R3(config)#interface fastethernet0/0R3(config-if)#shutdown

%LINK-5-CHANGED: Interface FastEthernet0/0, changed state toadministratively down%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0,changed state to down02:17:22: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.31.22 onFastEthernet0/0 from FULL to Down: Interface down or detached02:17:22: %OSPF-5-ADJCHG: Process 1, Nbr 192.168.31.11 onFastEthernet0/0 from FULL to Down: Interface down or detachedStep 5: Re-enable the FastEthernet0/0 interface on the R2 router.R2(config-if)#no shutR2(config-if)#end%SYS-5-CONFIG_I: Configured from console by consoleR2#

Step 6:Re-enable the FastEthernet0/0 interface on the R1 router.Notice that an adjacency is formed with the R2 router. It may take up to 40 seconds for the R2router to send a hello packet.R1(config-if)#no shutdown

Step 7:Use the show ip ospf neighbor command on the R1 router to view the OSPFneighbor information for that router.Notice that even though the R2 router has a higher router ID than R1, the R2 router has been setto a state of DRother because the OSPF priority has been set to 0.

R1#show ip ospf neighborNeighbor ID Pri State Dead Time AddressInterface192.168.31.22 0 FULL/DROTHER 00:00:33 192.168.1.2FastEthernet0/0R1#Step 8: Re-enable the FastEthernet0/0 interface on the R3 router.Notice that an adjacency is formed with the R1 and R2 routers. It may take up to 40 seconds forboth the R1 and R2 routers to each send a hello packet.R3(config-if)#no shutdown